Abstract: Composite materials contain fibers from natural sources and polyamides, wherein the polyamides have a softening point below 220° C., and a heat deflection temperature above 50° C. The polyamides consist of a) 30 to 70 mol % dimeric fatty acids, b) 30 to 70 mol % aliphatic dicarboxylic acids, c) 70 to 98 mol % aliphatic diamines, d) up to 25 mol % cycloaliphatic diamines e) up to 20 mol % polyether diamines, wherein aliphatic dicarboxylic acids are selected from linear, non-branched C10 to C18 dicarboxylic acids, and wherein the weighted average number of C-atoms is between 11.5 to 14.5, and the sum of mol % for acids and amine each add to 100.

Abstract: A process for bonding at least two substrates with a hotmelt adhesive using microwave energy is provided. The process includes applying a microwave-activatable primer to a least one of the substrates and applying a hotmelt adhesive to a least one of the substrates. The method also includes pressing the substrates together so that the microwave-activatable primer and the hot melt adhesive are between the substrates, and exposing at least the microwave-activatable primer to microwaves to heat the hotmelt adhesive. The present invention also provides a process for spraying a hot melt adhesive onto a substrate where the hot melt adhesive includes nanoparticles having ferromagnetic, ferrimagnetic, superparamagnetic or piezoelectric properties.